Simulating the hysteretic characteristics of hard magnetic materials based on Nd2Fe14B and Ce2Fe14B intermetallics

Abstract

The Ce2Fe14B intermetallic, like Nd2Fe14B, has the tetragonal Nd2Fe14B-type structure (space groupP4(2)/mnm), in which Ce ions have a mixed-valence state characterized by the coexistence of trivalent 4f(1)and tetravalent 4f(0)electron states. Despite the fact that the saturation magnetization, magnetic anisotropy field, and Curie temperature of the Ce2Fe14B intermetallic are substantially lower than those of Nd2Fe14B and Pr2Fe14B, Ce2Fe14B retains the capacity of being able to be used in the manufacturing of rare-earth permanent magnets. Moreover, at low temperatures, the anisotropy field of Ce2Fe14B is higher than that of Nd2Fe14B, and Ce2Fe14B does not undergo the spin-reorientation transition. In this respect, studies of (Nd, Ce)-Fe-B alloys, which are intended for the improvement of the service characteristics-to-cost ratio, are very relevant. A model and algorithm for calculating the hysteresis loops of uniaxial hard magnetic materials with allowance for the K(1)and K-2(K-2> 0 and K-1> 0 and K-1< 0) magnetic anisotropy constants were developed and allowed us to obtain data on their effect on the parameters of hysteresis loops for a wide temperature range (0-300 K). The simulation and analysis of hysteresis loops of the quasi-ternary intermetallics (Nd1-xCex)(2)Fe14B (x = 0-1) was performed. Results of the simulation indicate that the alloying of the Nd2Fe14B intermetallic with Ce tox= 0.94 (1) does not completely eliminate the negative effect of spin-reorientation phase transition on the residual magnetization of the (Nd1-xCex)(2)Fe14B intermetallic and (2) slightly decreases the slope of magnetization reversal curve.